1. Field of the Invention
The present invention is related to a positioning structure of an inner and an outer insulation sleeve member for an antenna; and especially to such an antenna of which an outer insulation sleeve and an inner insulation connecting rod (both are sleeve members) can be directly engaged with each other when in assembling to increase the torsional strength of the antenna in positioning in the peripheral direction of these inner and outer sleeve members.
2. Description of the Prior Art
Fixed antennas used in a mobile phone as an example mostly each uses an internal helical coil as a main element for transmitting and receiving signals. The bottom end of the helical coil and a metallic connecting seat are connected with each other, while on the other hand, it requires an outer insulation sleeve and an inner connecting rod to position and insulate itself.
Such a fixed antenna used in a conventional mobile phone can be positioned by primary connecting of the helical coil with the metallic connecting seat and then by connecting the outer insulation sleeve member (i.e. an ordinary cap) with the inner connecting rod. Such a connecting structure can further be combined firmer through a procedure such as high frequency melting-connecting; hence it must have equipment for melting connecting. Alternatively, the related members including the helical coil and the metallic connecting seat having been positioned can be placed in a die; and then the outer insulation sleeve is formed during injection enveloping. However, these processes for obtaining such structure is inconvenient by the necessity of placing the primarily connected members into a die for processing, and production of each article must be done in the die, yield of the products thereby is limited.
Although there have been the devices to direct connect by engaging an outer insulation sleeve with an inner connecting rod to form some antenna assembling structures now available, they can reduce extra procedures of processing to speed up production. However, such assembling structures generally are not quite stable, dropping can often happen when users of mobile phones fondle with antennas or are inadvertent in use. The torsional strength of such direct engaging structures available now generally is hard to pass severer regulations of examinations.
The object of the present invention is to provide a positioning structure of an inner connecting rod and an outer insulation sleeve (both are sleeve members) for an antenna, wherein, when the inner connecting rod of a helical coil and the outer insulation sleeve are shaped respectively, they can be engaged with each other with engaging means provided thereon, and synchronic positioning in the peripheral direction can be done at about the top ends of them, in this mode, the torsional strength of the antenna can be increased, such antenna can be manufactured with a high rate and a high yield.
In order to get the above stated object, the outer insulation sleeve of the present invention is made to have a top sealed end and a bottom opening, and an inner bore gradually enlarged from the top to the bottom thereof is provided therein, an upper inner annular recess and a lower inner annular recess are provided along the longitudinal wall of the inner bore. The inner connecting rod is provided thereon in coincidence with the structure of the abovementioned inner bore respectively with an outer rod portion, an upper and a lower annular protruding rib, the inner connecting rod can be inserted from the abovementioned bottom opening into the outer insulation sleeve. The outer insulation sleeve is provided near the inner top surface thereof with pending tongs, while the inner connecting rod is provided thereon with notches having corresponding shapes to the pending tongs respectively; thereby, the pending tongs can be inserted into the notches for positioning in the peripheral direction when the outer insulation sleeve is slipped over the inner connecting rod for connecting.
As to the pending tongs and the notches matching mutually, the pending tongs had better each be narrower at the lower end and wider at the upper end thereof for convenience of insertion positioning axially. In another preferred embodiment, the outer insulation sleeve and the inner connecting rod had better have their respective lower inner annular recess and the lower annular protruding rib provided with a stop portion with a truncated conical shape.